The Dogged Villainess and the Otome Protagonist

Violet is the daughter of the most influencial family among the crown prince's backers, the president of the crown prince's fanclub, and the fiancee of the first prince. She lived a perfect life... until she became the ex-fiancee of the crown prince.
On the eve of her 20th birthday, she was beheaded for the attempted murder of Daisy Baker, the commoner who also happens to be the crown prince's lover and new fiancee. When she next opened her eyes, she found herself in her bed 10 years in the past. Realizing she was given a second chance by fate, she vowed not to repeat the same mistakes. She then picked up a knife and went to pay Daisy Baker a little visit.